1. Field of the Invention
The invention relates to an injection molding device; in particular, for rubber, caoutchouc or similar materials such as elastomers, thermoset plastics and cross-linkable polymers.
2. Description of the Related Art
EP 0 287 001 A1 relates to a device for the injection molding of materials which comprises a plasticizing unit having an extruder outlet, the device further comprising an injection unit having an injection piston and an injection channel having a discharge opening. The extruder opening of the plasticizing unit is connected to the discharge opening of the injection piston for filling the injection unit. For the injection process, the extruder outlet is separated from the discharge opening and the injection channel is connected to a mold.
DE 91 10 240 U1 describes an injection molding device in which the plasticizing unit is firmly connected to an injection piston through which a feed channel passes leading into the injection cylinder. The end turning away from the injection cylinder is connected to an extruder outlet of the plasticizing unit. The mouth of the feed channel is located at the tip of the free end of the injection piston which tip is conically shaped. The bottom surface of the injection cylinder is formed by an insert and has a conical shape which corresponds to the shape of the free end of the injection piston. A discharge opening in the insert is aligned with the mouth of the feed channel in the injection piston. For filling the injection unit, the discharge opening is closed with a locking bar and material is fed from the plasticizing unit into the injection cylinder via the extruder outlet and the feed channel, the injection piston travelling accordingly. After that, the locking bar is drawn back and the injection unit i s coupled to a mold. Then, the injection piston is entered into the injection cylinder, wherein the check valve in the feed channel is pushed into a closed position and the material is pressed from the injection cylinder into the cavity of the mold. When the injection piston has completely entered the injection cylinder, the orifice of the feed channel is in connection with the discharge opening. After a certain time, the injection unit is separated from the mold by drawing the vulcanized piece out of the injection channel.